Collision detection is the determination of whether or not two or more entities make contact with each other during gameplay.

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Deforming surfaces

I try to accomplish an deforming physic behaviour for levelsurfaces, but don't get an idea how to start with the implemenation so far. Regardless of the shape from the surface (planes, cubes, ...
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1answer
1k views

How to resolve concurrent ramp collisions in 2d platformer?

A bit about the physics engine: Bodies are all rectangles. Bodies are sorted at the beginning of every update loop based on the body-in-motion's horizontal and vertical velocity (to avoid sticky ...
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1answer
330 views

What exactly is the difference between separation and obstacle avoidance

I've been reading some literature that explains both separation and obstacle avoidance. On first sight, they both seem very similar in what they are supposed to do: keeping objects apart form each ...
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2answers
321 views

How to make it so units don't stack up in one location? [duplicate]

Possible Duplicate: Is there a simple way to stop enemies standing in the same spot? So I'm making a game in AS3, it's a strategy DotA-like game (for flash game equivalent, there's UDE) so ...
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1answer
516 views

What do I need to do to my slope collision detection to prevent the player from passing through my collision?

I've recently implemented slope collision detection for my project. The issue I'm having is that the character occasionally passes through the line. This usually occurs when the characters ...
2
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1answer
665 views

Can Bullet Physics (or another 3d physics engine) use callbacks in my engine to check static geometry?

I'm wondering if it's possible to use or hack Bullet 3d Physics (or another free 3D physics engine) so that I don't need to "import" my static geometry into Bullet - instead I want to do it the other ...
2
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1answer
2k views

Collision detection between a sprite and rectangle in canvas

I'm building a Javascript + canvas game which is essentially a platformer. I have the player all set up and he's running, jumping and falling, but I'm having trouble with the collision detection ...
2
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2answers
565 views

3d Collision detection help xna?

I was hoping if you could help me out here. I'm developing a 3d table tennis game, and got the collision detection working perfectly when the ball hits the racket. However, now I would like the ball ...
6
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1answer
1k views

Minecraft-style player-gound collision detection

The title pretty much says it all... (Minecraft is a game consisting of evenly-spaced cubes for terrain, like voxels) Note: I am using C# XNA. I am pretty sure AABB is the way to go, yet I don't know ...
9
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3answers
588 views

How to separate colliding objects without creating more collisions

Suppose I use a simple discrete collision detection system where I move all objects then check for collisions. I want any colliding objects to be separated (of course) and assigned appropriate ...
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5answers
979 views

How do I set up moving platforms in a 2D side scroller to interact with the player properly?

Edit: I changed the way that gravity was applied so that it is applied even when a player is standing on a block, so instead of the game outputting that you are stepping on a tile as true and false ...
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3answers
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How can I determine the velocity after impact of a 2D ball collision?

Consider two balls moving towards each other. Each has a given mass and velocity. Assuming the balls collide, how can you determine what direction the balls will take afterwards? (taking into ...
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2answers
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How do I handle collision detection so fast objects are not allowed to pass through walls?

I'm creating a 2d sidescrolling shooter, and I'm having a little trouble with collision detection for the bullets. Everything including the bullets are objects with their own polygons / update ...
0
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1answer
157 views

How can I handle transferring a character from one collision surface to another?

I've been trying to modify some slope code from an example I've found but I've come across an issue the way the method is designed it attaches the current slope and then based off that slope ...
27
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7answers
19k views

most efficient AABB vs Ray collision algorithms

Is there a known 'most efficient' algorithm for AABB vs Ray collision detection? I recently stumbled accross Arvo's AABB vs Sphere collision algorithm, and I am wondering if there is a similarly ...
1
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1answer
1k views

Line segment / circle intersection - X value seems wrong?

Major Edit I'm making a Breakout clone, and having difficulty with collision detection between a circle and line segment. Apologies, my earlier question was a result of frustration and no sleep :) ...
9
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1answer
3k views

Circle-Line Collision Detection Problem

I am currently developing a breakout clone and I have hit a roadblock in getting collision detection between a ball (circle) and a brick (convex polygon) working correctly. I am using a Circle-Line ...
3
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1answer
2k views

2D circle / rectangle collision detection issue - brief overlap

I'm currently trying to build a Breakout clone as a first step into game development. I'm using the following collision detection code (adapted from ...
5
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4answers
6k views

2D Platformer Collisions

I've basically asked this question before, and I know it's been asked probably a billion times, but I still can't seem to do it. All I want to know is how I should go about doing basic 4-way, ...
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1answer
510 views

Updating XNA BoundingSphere - sphere moves in opposite Y direction?

In my players update method I calc the new world matrix then I update a boudingsphere by: MyBoundingSphere = MyBoundingSphere.Transform(World); However when the the model's World has moved ...
3
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3answers
3k views

How can I implement fast, accurate 2D collision detection?

I'm well aware of how to detect if two or more 2D objects collide but I'm interested in how to decide whether to check for a collision. In previous projects, I just had every object check against ...
4
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1answer
2k views

How can I detect collision between a circle and a rectangle?

i'm trying to make a clone of brick breaker, one problem that i am running in to is to do with collision. i know how to detect if a collision has happened but i do not know how to check what side of ...
5
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2answers
515 views

How to detect collision with non-rectangular objects in 2D games?

Detecting collision with rectangular objects is quite easy. I am able to write simple tile based games. Now I want to learn to write non-tile based games in which objects may not be rectangular, for ...
3
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3answers
967 views

XNA: Perform Collision Detection Against 3D Scene Geometry

How would one perform collision detection between a simple scene like the one below and a simple object like a sphere? I assume the best solution would involve convex hulls in some way but I have no ...
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4answers
2k views

Basic 2D game collision

I've been trying to program a game for the past while and I can't ever figure out one thing: collision detection. I can get up+down and left+right to work, but when I put them together, they interfere ...
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4answers
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How to deal with corner collisions in 2D?

I'm writing a top down 2d XNA game. Since its my first I'm trying to write the physics and collision stuff myself to learn it. Whenever my player sprite character attempts to move into a position ...
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3answers
4k views

Clean way to detect collision of object with box2d

I have been looking into box2d (in java with libgdx) lately and have been trying to create my own custom bounce effect (I increase the Restitution after the first bounce) To do this as a test I ...
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1answer
876 views

How to find which side of a collider has been hit from hit.normal?

In Unity3d, i can get the normal of the surface with which the collider collides using hit.normal, but is there a way to find which side has been hit what is provided bu Unity3d? One solution is to ...
5
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1answer
3k views

How can I set up a Pong-style game using the physics system in Unity?

I've just been using Unity and chose to learn it by making a Pong game which sounded simple enough as a "hello world" type of game. My goal was to try and encompass enough of the built in engine ...
6
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1answer
936 views

XNA Platformer Collision: PerPixel vs Rectangle

I'm writing a platformer engine with XNA and was wondering what method for handling collisions I should use. Would I be seeing some performance issues if I were to try and have PerPixel collisions? ...
7
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3answers
752 views

Polygon editor to draw collision data over image

I need an editor to plot a polygon over the texture for of a ship in my game. It would look like this.. Where the red is the collision outline and the image is the texture. I want to store the ...
15
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1answer
825 views

How to resolve collisions of compound shapes using SAT?

SAT is a decent way to determine collisions between arbitrary convex polygons. You'll even get the vector that is needed to resolve a collision. To resolve collisions between complex (non-convex) ...
3
votes
1answer
232 views

Collision Managers and bitmaps

I am rewriting a game I made to use a (custom) collision manager that uses the minimum displacement method. As of now, my simple manager can only recognize and act on a couple of shapes - Circles and ...
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1answer
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Sphere collision response

I have simple mechanism for testing of two balls colliding: private static boolean isColliding(float firstBallX, float firstBallY, double firstBallRadius, float secondBallX, float secondBallY, double ...
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1answer
969 views

Collision detection problem

I am a novice in android. It's my first game, so I am trying to make a frogger clone. I am getting a problem in collision detection. In logcat, even though the frog is not moving and not colliding ...
12
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3answers
4k views

2D game collision response: SAT & minimum displacement along a given axis?

I'm trying to implement a collision system in a 2D game I'm making. The separating axis theorem (as described by metanet's collision tutorial) seems like an efficient and robust way of handling ...
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1answer
2k views

Setting up collision using a tilemap and cocos2d

I'm building my first platformer using cocos2d and a tilemap. I'm having trouble coming up with a decent way of determining if the character is colliding with an object. More specifically, in which ...
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1answer
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What is wrong with my collision detection code?

I want to check collision detection between two bitmaps but I am not getting how to do it. I read several queries and tutorials but didnt get properly. I want to check by their width and height. I ...
6
votes
2answers
457 views

Is it possible to have concurrent collision detection where every entity acts at exactly the same time?

There are many algorithms that can be used for collision detection. In many cases we check for an overlap in coordinates of an entity. If we make a triangle a,b and c. We have 2 entities at a and b ...
8
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1answer
2k views

Am I going to regret using a color based collision detection system?

I'm just getting started build my first game with XNA (I'm experienced with C# but not games). I'm building a pretty simple top down 2d shooter. I read this tutorial on using a color based collision ...
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2answers
674 views

HTML5 collision with images

Can anyone please help me out with a small test game I'm creating. I'm basically creating this game to learn a few things about HTML5 and so far it's all been good. I've been able to create a canvas ...
7
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2answers
2k views

How do I find the point of impact with 2D per-pixel collision detection?

I'm creating a platformer and have implemented per-pixel collision detection. However, this has caused 2 obstacles that I've yet to figure out. The first obstacle, which this question is about, is ...
4
votes
2answers
2k views

Algorithm to fit shapes to 2D grid?

Let's say you have an n-by-m grid. Some squares are occupied, some are not. You want to know where in the grid you can fit arbitrary shapes such as to not hit an occupied square. The shapes would ...
4
votes
3answers
4k views

How to handle platform collisions in a 2D game?

If I have a map in my platformer game and I want my character be able to jump on some platform, for example. Is there an easy way to tell the game where the platforms are and where the player can jump ...
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1answer
2k views

How can I cancel a contact in a b2ContactListener?

To know when contacts happen we can derive from b2ContactListener and implement our own solution which is great. I'm wondering is there anyway we can cancel a contact, that is to say when we hit begin ...
11
votes
3answers
4k views

Collision resolution in case of collision with multiple objects

I have static objects and movable objects. The collisions are detected using the separating-axis-theorem. For example, in this situation I have two static objects (in red): and a movable object ...
1
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1answer
855 views

Can you help with collision detection and response in a 3D car racing game?

I am trying to implement the collision detection and response in 3D car racing game. I have a car model, for collision I am assuming my car as a cuboid. my collision detection with walls is quite ...
22
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4answers
2k views

Momentum and order of update problems in my physics engine

This question is a "follow-up" question from my previous one, regarding collision detection and resolution, which you can find here. If you don't want to read the previous question, here's a ...
0
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2answers
505 views

C# XNA Framework Paddle Collision Problems

I am trying to make a pong game that uses a burger as a ball and a plate as its paddle. I have everything right except that the burger goes right through the plate. Can anyone help me? using System; ...
0
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2answers
943 views

How to coordinate sprites, player's position and collisions in a Bomberman-like 2D game?

I'm programming a Bomberman in Java (my first game) and I'm having problems with the player's sprites and position in the map. I'm using a 2D integer array to represent: Unbreakable blocks ...